Suspension bridge



May 8, 1923.

- V. L. SULLIVAN SUSPENS ION BR IDGE Filed Nov. l, 1921 2 Sheets-Sheet 1 K Sullivan.

INVENroR.

A-rroRNsYs..

May s, 1923.

v. L. SULLIVANv SUSPENSION BRIDGE Filedov. :1, 1921 sheets-sheep 2 Sullivan.

l INveNran- AU-nfnivs.

- AVX -is a specification.

Patented May 8, 1923.

oniricav STATES i SUSPENSION BRIDGE;

Application*meaNovember 1,1921. sieria1-No. 512,o12.`

T0 all whom it may concern: -1

Be it kno-wn that,I,VnRi\Ioi\rL. SULLIVAN, a citizen of the United States, residing at El Paso, inthe county of El Paso and State of Texas, have vinvented'.'Improvenients-.in Suspension Bridges, of which the following My invention is an improvement inthe constructionof bridges, and relates more especially to suspension bridges in which the floor for thet'raiiic is suspended by rodsl from supporting cables extending ,over towers with. their-ends'anchored at .or 'beyond the approaches to the bridge, the cables describing an arc in the span betweenthe ltowers and from the towers tothe anchors.

In the use of a suspension bridge ofthe Vordinary type the floor over which the traffic passes 'is subjected to an undulating' or wave motionthat -varies with ,respect tothe main 'span as the load approaches the center oi said span-the point `of greatest undulation orsag being nearer `the towers which support-the cables and gradually de- ,creasing to the center at'which latter point there isthe minimum undulationorsag-fa and this variation is caused by the, deflectionvof vthe cables: in vboth directions from v.the locationrof'the'load. moving` over the bridge, inasmuch asythat portion of each cable extending from the location of Vthe,

load to the nearer tower assumes .with Vthe other or longer portioni ofthe cable an .obf tuse angle of lesser'degree than when the load is at the center -of the `span where ythev pull is equalized; in other words, the 4sag in the supporting cables from a true are becomes more-evenly divided as? the load ya] oproaches Athe f-center of 'the span'4 rom 'either tower.v 'In they construction of bridges of this type itiscuStOmaryto `so arrange the supporting' cables as to provide for a maxlmumsag, consistent `with the .required strength, for said cableswill then sustain a greater load than if the radii arclis larger.

Fig. 5. 1 jected to a lateralv or swaying motion,vas "well yas a` lifting motion, under stress of 4Bridgesof this character areyalso subwind, and of course the undulating', swaying, and lifting motions `are not only objectionable to those using .the bridge butj the effect on theV structure has ai' tendency: v to .gradually weaken the same. f y With these objections to the ordinary'sus- -pension bridge in `mindit -is the-purpose ofy my invention/to soimprove the generalijcon- 7 VERNON s ULLI'vAN, or EL Pso, TEXAS.

struction of this special type lof-bridgelasfto y make it practically'.anti-undulating forthe more,convenient Ypassagegof vehicles yand other traffic thereover, land* falso-2 'provide` against swaying or Ilii'tingfofthe] main' span i under the pressurepf high winds-.- l x 1 My invention therefore consists` in the particular.` construction fof# ay suspension; 65,

bridge whereby in one:linstance'lprovide in .connection vwith the usual.` main cables, suspension,` rods and oor structureawhatl term anti-undulating. cables, which; are fastened to and extend fromthe base yportion or pier ofeachytower andare connected attheir outer ends -to'themain cables, the number of anti-undulating cables vand distance 'f of their connectiontothe main cables away from the towersv depending :upon Ithe length of the bridge structure, and in co'nnection therewith provideyanti-sway cables iwhi'ch" are' likewise attached 'to the `piersofg the towers and yare arranged with respect to the j main cab-les and- Hoor structure, to which'.

latter they are also connected, whereby.. the

bridgev constructed invention..

Fig. 2Q i l Figs. 5 and 6 'are' Fig 2'v is a similar view 4on a largerls'cale kof "a portiononly ,of the lbridge toi more clearlyshow certain'features of the present construction. y l is afp-lan View of-FigQ. f Fig. 4 is as sectional vewfonjlinefaof* detail View; in; Side f elevation and plan, respectively,l to =more clearlyV illustrate thefloor .structure includf ing the sideirails and truss rods for bracing ,the'same.

FigLIfS-"i's acdiagrammatic view lto'illus- ,tra'te the sag or undu'lations which occur'in the ordinary form ofy suspension jbridgei carryingo utv my invention I employ ythelusual` towers l0, 10,",andmain su'pporting cablesll', 11, the `latter passing-overthe l tops. o f the ytowers in the.A usual manner and are suitably anchored 4 in the ground iattheir lic ends. IThe heightfo the towers: fvvithfrespect tol the lapproaches `'to thevmain span and length of the latter will determine the arc of the main cables in the span between the towers, and in the present insta-nce the conventional arrangement in this regard may be provided. I also employ the conventional form ol' floor structure for the trallic, in which there are cross-beams 12 for the lloor-joists 13 on which the plank# ing 14 is nailed; and in the present instance the rods, as 15, by which the aitor'esaidlleor beams' are suspended from the main cables 11 arepreierably disposed so as to. distribute Jhellead ensaid cables, for which` purpose each floor-beam 12 isV suspended at each end by two rods, 15, 15, that diverge from the beam to widely separated points on the cableV above. This arrangement of' the Hoor suspension rods is off advantage in distributing the' weight ot the load passing directly over any one of the beams 'tov ditierent points on the main cables, 'in-stead ofl points immediately above, thus not only relieving' said cables b y distribution of the load but also tending to minimize undulati'ons in the span of the bridge.

The bridge is preivided at each side ef the floor' with the' usual hand-rails 16' supported byk posts 17 rising from the tloor-beams 12, to which latter they are-securely ia'stene'd", and. this structural part of the bridge is thoroughly braced' by diagonal strips 18,

l extending from the top ot each post to the beam supporting the neX-t post in both directinns'. rlhis arrangement of the bracing strip's stifens. the floor structure and in connection with the aforementioned disposition of the 'suspension rods serve to distribute the'v weight of they load` passing over the bridge. As will bey understood the Hoor ot the bridge; is supported en' a line immediately above the piers from the main cables which pass` over the upper ends of" the towers rising from said piers,l the' towers bei-ng` locatedv at opposite sides offthe'bridge structure, and that the parts hereinbefore described comprise the main'structure of a sus Dension bridO'e in the )resent'insta-nce providing for lightness and stability".v

As a part ot the construction of the suspension bridge', for the purpose of minimizing, it not entire-ry eliminating, the' undulating or wave motion: to which the floor is sub'iected during` the passage of a vehicle or other load over the same l provide a series of cables, 19, which are securely fastened at their inner ends to the piers of the towers and extend in both directions therefrom for' connections directly to the main cables 11 at a suitable distance from saidtowers, and these` cables, 19,- li have `termed anti-undulating cables, each becables act` to stabilize or' reinforce the main supportiing4 cables to: prevent undulating motion of the bridge, as hereinafter more fully explained.

In connection with: the anti-undulating `callrle's ly provide the bridge structure' with cables adapted to serve the purpose'v of preventing a swaying or lifting' motion ot the bridge spans` during l'iigh winds, those', as 22, used in'- conjlunction with the main. span extending' from the piersr atv each. end of said span. to the center of' the cables, being preferably crossed under'the floor ot the bridgey as shown in the drawings, similiar cables, asl 23, extending" from the piers to the ends of the shorter spans and likewise crossed under' the' tl'o'or, and t@ reinforce thesey anti-sway cables'or increase their" eife'ctiveness in operation they' are connected at intervals by rods 24 to the ends: @t the floor beams 112 and by'v rods 2da' to eachother, a. suitable number of.' tie-rods being used as required.

lt will be noted thatv bothv anti-undulating cables and cables preventing swaying" m'oti'en are fastened directly y to@ the ypiersoi the towers at a distance below the pl'anreef the floor ot' the'bridge to exert' the propery tension: oni the main cables to coun-l Itcnactthe effect off. a load' as it passes over the bridge: from one' end tof` the other,V and Ythat they cooperate to increase the stability of the bridge.

By reference to the diagrammatic view, Fig; 8v oit-the' drawings, showing' the ina-xlivmum sag' trom. a true1 arel oni the' unrestricted cables el an ordinary suspension bridge, it will be noted that, in respect to the mai-n span, as' the load leaves a1 tower and` approaches the center of* the span it' will, at the` point 'a sag' orf deflect the cable B so that it will' assume obtuse angle of much lesser degree' than when it arrives at the lrenterv of the span or' point e, the angle of deflection. becomingl greater' from' point a to point e,- as indicated at' c, the undulation orv sag in the cables beinfr'therefore greaterA at the point a' andvk diminishing to the center of thev spanV or point' e. providing' the anti-undulating cables and conmeeting thenlix rn substantially the manner shown and described thev main cables are 1li-,Meara reinforced lin 'such manner that the usua'lundeletions 'or wave motions on "the aber of :th'bridge are eliniinatedfthe operat'ionof these antianhaulating `@abn-,sj"being further augmented by the 'disposition of the suspension rods sadness-reds di the; 'man1 bridge structure. For the purpose of explanation we 'will assumethat a. load 'passing over 'the bridge arrives at the dentelof tnefrst lo or shortspam thevjanti-'yundulating cablesfin the v main span and other short span', lin connection with' the 'corresponding antilsw-ay cables will prevent saggia-g of, the floor, for

tli'euifeason that the inainpoables are yheld ,ai the true are at other peints than where the load is located. likewise the mainsu'pporting cablesr will be held at the true arc as the load passes along the main span beabove the load.

The disposition of the anti-sway cables are such that they reinforce the bridge against lateral movement, and also against a lifting motion, to which ordinary suspension bridges are subjected by wind pressure, the crossing of these cables under the fioor, and connecting them to the floor beams increasing their eifectiveness.

By the use of the anti-undulating cables a greater deflection 0r more sag may be used in the construction of the main cables permitting the use of lighter cables without weakening the bridge, and by reducing the undulating action, or entirely eliminating such action, with the improved bridge construction herein shown and described the bridge will not only provide a more pleasant passageway for traffic but will be safer, as lwell as more durable and consequently last a longer period of time notwithstanding its lighter construction.

To provide for connecting the supporting-rods 15 t0 the main cables and oorbeams, respectively, an -ordinary metal clamp 15a is used on the cables 11, and to the underside of each end of the beam l2 is bolted a bracket-plate 25 having opposite ears 25a pierced to receive said rods (see Figs. 5 and 6) the brackets at the ends of some of the floor-beams being also provided each with an additional apertured ear, 25h, for connecting thereto the truss rods 24 used in connection with the anti-sway cables.

I claim 1. In a suspension bridge the combination with the bridge structure comprising towers, supporting cables extending between and over the towers to suitable anchors, and a oor structure including cross-beams suspended from said cables, ofv anti-sway ca-l bles fastened to the lower portions of the towers and extending across the underside ere-1e nearer-ehe maaepeatdthe @esta er the cables at opposite' sides'oflthefbridge, respectively, and rods connecting saidantivsway'cables to *the 4beaifnsoi the floor strucy 'fu'fe-qg. 1 Y; 2;;111; suspensionl'brdge th-efcvombinatron withV the bridge structure comprising attached to 'the eenterbf the main cables I' between lthe `'towersj and tothe abutments of fthe bridge, and vertical rods connecting said anti-sway cables to the beams of the floor structure, substantially as shown and for the purpose set forth.

towers, 'supportingcablefs `exter'iding between and over theto'wersto suitable' anchors," 'and l,

'a floor i structure including "cross-bcamsZ suswpende'dffro'n said cablesof' anti-swayca@ bles -`fastened to the lower portions of lthe towers 'and extending in tippen-ite directions from uiem'tbwers across theundersde' of' the.

licor 'of `the 'main span and I s hortspa'n's and' v 3. In a' suspension bridge the combination with the bridge structure comprising' towers, supporting cables extending between and over the towers to suitable anchors, and a iioor structure including crossbeams suspended from said cables, of antiundulating cables fastened to and extending from the lower portions of the towers and connected at their outer ends to the main cables at different distances frompsaid towers, a plurality of said cables being so connected to each portion of thermain vcable between the towers and center of the main span, a Aset of anti-sway cables also fastened to the lower portions of the towers yand extending across beneath the floor of the bridge'to the center of the main cables at opposite sides of the bridge,respectively,-

and rods connecting the last mentioned cables to the beams of the floor structure at different points, substantially as shown and for the purpose set forth; 1

4. In a suspension bridge the combination with the bridge structure comprising towers and supporting cables extending between and over the towers to suitable anchors, of cross-beams upon which the floor v l izo ity of said cables 'being so connected to each` bridge. respectively, vertical rods connect# ing the last mentioned cables tothe floor- .beams and tie-rods connecting said cables together, substantially as shown and described.

5. In a suspension bridge the combination with the bridge structure comprising towers and supporting cables extending between and over the towers to suitable anchors, of a floor structure comprising crossbeams upon which the ioor-joists and planking aresupported, rods connected to the ends of each floor-bea1n and diverging in the longitudinal line of the bridge for connection with the main cables, posts rising from the ends of the beams to carry'the hand-rails, and bracing strips crossed between the posts and therefore extending from the ends of the beams in oppositedirections to the upper ends of the posts; to-

bles, a plurality of saidl cables being so con-k nected to each portion of the main cables between the tower and center of the rnain span, anti-sway cablesclossed beneath the floor of the bridge and connected to the center of the Ina-inl cables at opposite sides of said bridge, vertical rods connected to the last mentioned cables and to the floor-beams, at different intermediate points, and tie-rods `connecting said cables together, substantially as shown and for the purposes set forth.

VERNON L. SULLIVAN.' 

